The eclipse also turned the spotlight on a solar feature that doesn't often hit the headlines - sunspots.
By chance, at the time of the eclipse there was a massive sunspot the size of Jupiter on the face of sun. It generated a number of very powerful flares over several days - potentially very scary, as an ejection of solar matter and radiation directly towards the Earth can result in severe disruption to various crucial technologies.
Luckily this particular sunspot has moved out of view so it is no longer a threat. But it's dramatic appearance serves to remind us of the dynamic and often unpredictable power of our nearest star. There is still much about its internal workings that we do not fully understand, especially its magnetic fields.
Sunspots are dark patches on the face of the sun that develop and fade, and appear to move across the sun as it rotates. They can last anything from just hours to many days. They can grow larger and even merge with each other. So the very existence of sunspots shows that the sun is dynamic and constantly changing.
In fact the sun is full of twisting magnetic fields, and sunspots are locations where the magnetic field lines poke out from the visible surface of the sun. As you can see from the image above, the dark centre (the umbra) is surrounded by a less dark area (the penumbra). The umbra is around 2000 degrees centigrade cooler than most of the surrounding gas, which is why it appears relatively dark - this is where the magnetic field pokes out at right angles, and the strong magnetism prevents the outward flow of heat in this area. The penumbra is made up of closely-packed tendril-like features that all point into the centre of the sunspot - in this area the magnetic field lines are weaker and at a lower angle to the surface.
Sunspots often occur in pairs of opposite magnetic polarity, like the opposite ends of a bar magnet. The hot gas above sunspots is often thrown up high into the solar atmosphere, creating huge arching loops that link areas of opposite polarity, as you can see in this image.
There is still a lot that is not still fully understood about the processes involved in the sun's magnetic field. For example, exactly how is the Sun's magnetic field created? Alsoi the magnetic filed is suspected to be at the root of a currently unsolved mystery that particularly puzzles solar scientists, the 'coronal heating problem', or the way in which the the sun's outer atmosphere - the Corona - is heated to over a million degrees, when the surface is only (!) around 5700 degrees Kelvin. This is an area of very active research and so perhaps we will have some answers or at least more clues in the near future.
But for now, just enjoy these stunning images of just some of the many fascinating magnetic features of our sun.
Note: it's worth emphasising what common sense tells us - do not look at the sun directly, either with the naked eye or through a telscope, without a proper filter, as this can cause serious permanent damage to the eyes. For tips on methods for safe viewing of the sun see http://www.skyandtelescope.com/astronomy-news/observing-news/how-to-look-at-the-sun/
http://phys.org/news/2011-01-sun.html#jCp
http://www.astronomy.com/news/2013/10/astronomers-find-clues-to-decades-long-coronal-heating-mystery
http://smithsonianscience.org/2014/10/tiny-nanoflares-might-heat-suns-corona/
1. National Solar Observatory http://phys.org/news/2011-01-sun.html
2. NASA/TRACE. (Public domain) http://commons.wikimedia.org/wiki/File:Sunspot_TRACE.jpeg
3. Tomruen (Creative Commons) http://commons.wikimedia.org/wiki/File:Solar_eclipse_of_October_23_2014_start_of_partial.jpg